The invention relates to transportation systems of the kind comprising a guideway and a number of vehicles movable along the guideway. Although the invention is applicable to transportation systems for any purpose, including the transport of passengers as well as goods, it is particularly applicable to systems in which the vehicles are adapted to handle containers, that is to say for stacking, unstacking, sorting and moving containers as well as loading them into or unloading them from carriers such as rail vehicles, lorries or ships.
Conventionally, the loading of containers into and from ships is carried out by fixed dockside swing cranes and is a time-consuming operation requiring judgement and skill on the part of the crane operator as well as the use of additional manpower to effect the precise location of a container as it is set down in the hold of the ship or on the shore.
Also, time taken to load or unload containers is partly determined by the time taken for the crane to swing, unladen, to the stack of containers to collect the next container for loading or unloading. It is generally not practical for a plurality of cranes to operate on the same batch of containers simultaneously and consequently no loading takes place while a crane is returning to pick up another container. Furthermore, since the range of operation of the crane is comparatively limited, there is a limit to the number of containers which can be brought within the crane's range of operation and this may lead to delays between loading of stacks of containers while further containers are brought within the crane's range of operation. Road and rail vehicles may have to remain idle pending removal from them of containers which are to be loaded on board ship.
Accordingly, the invention sets out to provide a transportation system which, although not exclusively applicable to container handling, is particularly suitable for such purpose and may allow the substantially continuous loading or unloading of containers over a large area.